Communication systems utilizing binary pulses for high-speed message transmission generally require stabilization of the performance of their pulse-emitting components, whether they be primary sources such as traveling-wave tubes, lasers and the like or secondary treatment stages such as power amplifiers, in a condition of maximum efficiency as concerns both the shape and the amplitude of the emitted pulses. Such stabilization, designed to counteract the effects of temperature changes and aging, may be obtained by negative feedback with the aid of control signals derived from both the mean and the peak-to-peak power of the pulse sequence.
A signal proportional to the mean power of a series of unbalanced pulses can readily be produced by integration, pursuant to conventional techniques. To measure the peak-to-peak power--i.e. the RMS amplitude difference between the randomly alternating high-level and low-level pulses--it has heretofore been necessary, however, to use a detector of small time constant and an amplifier whose performance characteristics must be similar to those of the equipment designed to receive and demodulate the transmitted message pulses. These requirements can be satisfied only with rather complex and expensive circuitry.